Colonic transit, psychiatric factors and dietary intolerance will be evaluated in patients with the irritable colon syndrome. Normal subjects and matched psychoneurotic patients will serve as controls. Patients with the irritable colon syndrome will be recruited based on a negative "routine" evaluation and symptoms including abdominal pain, constipation, diarrhea, abdominal bloating and flatulence. Each of these symptoms will be scored for severity. Colonic scintigraphy will be employed to quantitate cecal-ascending colon emptying and the progression of luminal contents through the colon. Time distribution histograms, time activity curves and progression of the geometric center of the cecal instillate will be determined for each study subject. Psychiatric evaluations will include a psychiatric interview (DIS) and psychometric testing (MMPI, Beck Depression Inventory, Spielberger State/Trait Anxiety Inventory, Vocabulary Subtest of WAIS-R), and a special questionnaire. Dietary intolerances will be established by a comprehensive interview, symptom-diet checklist and completion of a home diary. An attempt will be made to correlate abnormalities in colonic transit with clinical symptoms and/or psychiatric and dietary factors. The effects of "provocative" and "bland" films on colonic transit will be compared in normal subjects, patients with the irritable colon syndrome and psychoneurotics. Provocation of anxiety will be documented by the Spielberger State Anxiety Inventory and measurements of urinary and plasma catecholamines. The effects of provocative meals on colonic transit will be compared in normal subjects and patients with the irritable colon syndrome. The mechanisms of provoked changes in colonic transit will be studied using pharmacologic interventions, such as adrenergic, cholinergic and opiate receptor blockers, prostaglandin inhibition and somatostatin to prevent the release of GI peptides.